{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-39855 in the wild and no public exploit code.","fix":"Upgrade to a fixed version.","what":"CVE-2026-39855 is a medium-severity vulnerability in mtrojnar osslsigncode, published on 9 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2026-39855 and fix it if it is affected.\n\nWhat it is: CVE-2026-39855 is a medium-severity vulnerability in mtrojnar osslsigncode, published on 9 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2026-39855 in the wild and no public exploit code.\n\nAffected product: mtrojnar osslsigncode. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-39855/ (Markdown: https://insights.sbomify.com/CVE-2026-39855/index.md)","id":"CVE-2026-39855","markdown":"https://insights.sbomify.com/CVE-2026-39855/index.md","name":"CVE-2026-39855","record":{"aliases":["DEBIAN-CVE-2026-39855","GHSA-76vv-x5rr-q3mr","UBUNTU-CVE-2026-39855"],"analysis":{"component_type":"developer_tool","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Authenticode signing tool","requires_auth":"none","summary":"An integer underflow in osslsigncode allows attackers to cause an out-of-bounds read and crash the application by providing a malicious PE file.","user_interaction":"required","vuln_class":"integer_overflow"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"osslsigncode","vendor":"osslsigncode_project"}],"cvss":{"score":5.5,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-191","name":"Integer Underflow (Wrap or Wraparound)"},{"id":"CWE-190","name":"Integer Overflow or Wraparound"},{"id":"CWE-125","name":"Out-of-bounds Read"}],"description":"osslsigncode is a tool that implements Authenticode signing and timestamping. Prior to 2.13, an integer underflow vulnerability exists in osslsigncode version 2.12 and earlier in the PE page-hash computation code (pe_page_hash_calc()). When page hash processing is performed on a PE file, the function subtracts hdrsize from pagesize without first validating that pagesize \u003e= hdrsize. If a malicious PE file sets SizeOfHeaders (hdrsize) larger than SectionAlignment (pagesize), the subtraction underflows and produces a very large unsigned length. The code allocates a zero-filled buffer of pagesize bytes and then attempts to hash pagesize - hdrsize bytes from that buffer. After the underflow, this results in an out-of-bounds read from the heap and can crash the process. The vulnerability can be triggered while signing a malicious PE file with page hashing enabled (-ph), or while verifying a malicious signed PE file that already contains page hashes. Verification of an already signed file does not require the verifier to pass -ph. This vulnerability is fixed in 2.13.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"osslsigncode has an Integer Underflow in PE Page Hash Calculation Can Cause Out-of-Bounds Read","id":"CVE-2026-39855","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"integer_overflow","year":"2026"},"n_packages":0,"n_references":3,"next":{"headline":"osslsigncode has an Out-of-Bounds Read via Unvalidated Section Bounds in PE Page Hash Calculation","id":"CVE-2026-39856"},"packages":[],"prev":{"headline":"osslsigncode has a Stack Buffer Overflow via Unbounded Digest Copy During Signature Verification","id":"CVE-2026-39853"},"products":["osslsigncode"],"published":"2026-04-09","related":[{"cvss_score":9.8,"headline":"Privilege escalation in n/a","id":"CVE-2025-70888","kev_date_added":null,"published":"2026-03-25"},{"cvss_score":7.8,"headline":"osslsigncode has a Stack Buffer Overflow via Unbounded Digest Copy During Signature Verification","id":"CVE-2026-39853","kev_date_added":null,"published":"2026-04-09"},{"cvss_score":7.8,"headline":"Memory corruption in n/a","id":"CVE-2023-36377","kev_date_added":null,"published":"2023-07-03"},{"cvss_score":5.5,"headline":"osslsigncode has an Out-of-Bounds Read via Unvalidated Section Bounds in PE Page Hash Calculation","id":"CVE-2026-39856","kev_date_added":null,"published":"2026-04-09"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-04-09","vendors":["mtrojnar"]},"summary":"An integer underflow in osslsigncode allows attackers to cause an out-of-bounds read and crash the application by providing a malicious PE file.","url":"https://insights.sbomify.com/CVE-2026-39855/"}